Semiconductor device and method for manufacturing semiconductor device

Abstract

A first connection portion and a second connection portion connect a first control gate to a second control gate, and are separated from each other. The first control gate includes a first disconnection portion between the first connection portion and a source diffusion layer closest to the first connection portion. The second control gate includes a second disconnection portion between the second connection portion and the source diffusion layer closest to the second connection portion. A first word gate and a second word gate are not disconnected in portions overlapping the first disconnection portion and the second disconnection portion.

The invention claimed is: 
     
       1. A semiconductor device comprising:
 a substrate; 
 a first word gate formed over the substrate; 
 a second word gate, formed over the substrate, which extends parallel to the first word gate; 
 a first control gate formed at a lateral side facing the second word gate in the first word gate; 
 a second control gate formed at a lateral side facing the first word gate in the second word gate; 
 a first connection portion and a second connection portion, formed over the substrate, which connect the first control gate and the second control gate, and are separated from each other; and 
 at least one diffusion layer, formed in a region located between the first connection portion and the second connection portion in the substrate, which extends from the first control gate to the second control gate, 
 wherein the first control gate includes a first disconnection portion between the first connection portion and the diffusion layer closest to the first connection portion, 
 the second control gate includes a second disconnection portion between the second connection portion and the diffusion layer closest to the second connection portion, 
 the first word gate is not disconnected in a portion overlapping the first disconnection portion, and 
 the second word gate is not disconnected in a portion overlapping the second disconnection portion. 
 
     
     
       2. The semiconductor device according to  claim 1 , further comprising:
 a third control gate formed at a lateral side at which the first control gate is not formed in the first word gate; and 
 a fourth control gate formed at a lateral side at which the second control gate is not formed in the second word gate, 
 wherein the third control gate includes a third disconnection portion at the same position as that of the first disconnection portion in a direction in which the first control gate extends, and 
 the fourth control gate includes a fourth disconnection portion at the same position as that of the second disconnection portion in a direction in which the second control gate extends. 
 
     
     
       3. The semiconductor device according to  claim 2 , wherein the first word gate and the second word gate are repeatedly disposed in this order,
 the first control gate and the third control gate are formed in each of a plurality of the first word gates, 
 the second control gate and the fourth control gate are formed in each of a plurality of the second word gates, and 
 the semiconductor device further comprises a third connection portion and a fourth connection portion, formed over the substrate, which connect the third control gate and the fourth control gate facing each other, and are separated from each other. 
 
     
     
       4. The semiconductor device according to  claim 1 , wherein a plurality of the first connection portions and a plurality of the second connection portions are alternately provided along an extending direction of the first control gate,
 the first disconnection portion is provided in the first control gate with respect to the plurality of the first connection portions, and 
 the second disconnection portion is provided in the second control gate with respect to the plurality of the second connection portions. 
 
     
     
       5. The semiconductor device according to  claim 1 , wherein the first connection portion is provided on one end of the first control gate and the second control gate, and
 the second connection portion is provided on the other end of the first control gate and the second control gate. 
 
     
     
       6. The semiconductor device according to  claim 5 , further comprising:
 a first word contact provided on at least one end of the first word gate; and 
 a second word contact provided on at least one end of the second word gate, 
 wherein the first word contact and the second word contact are not provided between the first connection portion and the second connection portion. 
 
     
     
       7. A method for manufacturing a semiconductor device, comprising:
 forming a first word gate and a second word gate over a substrate; 
 forming a conductive film over the substrate, the first word gate, and the second word gate; 
 forming a first mask film over the conductive film, and etching the conductive film using the first mask film as a mask, to form a first control gate located at a lateral side facing the second word gate in the first word gate, a second control gate located at a lateral side facing the first word gate in the second word gate, and a first connection portion and a second connection portion that connect the first control gate and the second control gate and are separated from each other; 
 forming a second mask film that covers the first connection portion and the second connection portion, and partially covers the first control gate and the second control gate; 
 performing etching using the second mask film as a mask, to form a first disconnection portion located between the first connection portion and the second connection portion in the first control gate, form a second disconnection portion located between the first connection portion and the second connection portion in the second control gate, and not to disconnect the first word gate and the second word gate; and 
 introducing impurities selectively in a region located between the first connection portion and the second connection portion in the substrate, to form at least one diffusion layer extending from the first control gate to the second control gate, 
 wherein the first disconnection portion is located between the first connection portion and the diffusion layer closest to the first connection portion, and 
 the second disconnection portion is located between the second connection portion and the diffusion layer closest to the second connection portion. 
 
     
     
       8. The method for manufacturing a semiconductor device according to  claim 7 , wherein in the forming of the first control gate and the second control gate,
 a third control gate is formed at a lateral side which is on the opposite side to the first control gate in the first word gate, and a fourth control gate is formed at a lateral side which is on the opposite side to the second control gate in the second word gate, and 
 the first control gate is connected to the third control gate at an end of the first word gate, and the second control gate is connected to the fourth control gate at an end of the second word gate, and 
 in the forming of the second disconnection portion, a connection portion between the first control gate and the third control gate at the end of the first word gate is removed, and a connection portion between the second control gate and the fourth control gate at the end of the second word gate is removed. 
 
     
     
       9. The method for manufacturing a semiconductor device according to  claim 7 , wherein in the forming of the second mask film,
 a region located at the same position as that of the first disconnection portion in an extending direction of the first word gate in the first word gate is covered with the second mask film, and 
 a region located at the same position as that of the second disconnection portion in an extending direction of the second word gate in the second word gate is covered with the second mask film.